Functional elements of metal having a flange of larger diameter which forms an attachment surface and having a centering section arranged with the attachment surface and extending away from the flange are widely used and well known for use in metallic components such as sheet metal parts. Examples can be found in the European patent specification EP 1116891 of the present applicants which describes a so-called RND nut. That is to say the functional element is formed in the named European patent specification as a nut element. There the centering section is formed as a riveting section which is deformed after or during the attachment in order to form a rivet bead.
The functional elements which enter into question can however not only be nut elements but can also be formed as bolt elements, for example as a bolt element similar to that of the German patent application with the official file reference 102004062391. The centering bolt shown there has a so-called skirt, which is ultimately also formed as a rivet section and is beaded over during the insertion of the centering bolt into a sheet metal part.
Functional elements can by all means have other forms. For example a bolt element can have a cylindrical shaft part instead of a thread which serves for the journaling of a lever, of a cable pulley or of another component. A hollow element similar to a nut element also enters into question in which a smooth bore is provided instead of a thread cylinder and serves for the journaling of a shaft. Furthermore, functional elements are known which can be formed to receive an inserted pin or a clip. In accordance with the invention, functional elements can also be designed to carry out the corresponding functions.
In the context of the endeavors to provide shape parts of low weight but of high strength, plastic components are frequently used nowadays instead of sheet metal parts, principally in the form of composite materials, such as for example plastics reinforced with glass fibers or carbon fibers, although other reinforcement materials can also be considered, normally those with high strength reinforcement fibers or fabrics formed from such fibers. Components of such plastics also frequently need to be provided with fastener elements for which a restricted selection of possibilities is already known. In this example press-in elements are for example known which are pressed into matched bores of the plastic materials, normally at elevated temperatures of the material. The plastic material flows around the insert and into undercuts provided there and anchors the inserts in the cold state. The inserts can for example be provided with internal threads. Such inserts have indeed their justification but they are mainly only restrictedly loadable, because they could otherwise be pulled out of the plastic part or out of the plastic component. The use of such inserts is particularly problematic with relatively thin plastic components. Fastener elements are also known which take the form of a wire hoop with eyes at both ends of the wire hoop which are secured with a blind rivet to a component. A screw part which is rotatably journalled within a thin sheet metal mount or holder is secured to a further plastic part, likewise by means of blind rivets which secure the sheet metal mount or the holder to the plastic component. The screw has a cylindrical projection with bayonet-like grooves and can be secured by rotation through 90° to the wire hoop at the first component so that the wire hoop is received in the bayonet grooves, whereby the second component is attached to the first component. Such attachments are indeed expedient for thin components, such as panels in aircraft or sport cars which have to be quickly removed and reinstalled, the attachment itself however only permits a restricted clamping force. Also the riveted connections cannot be very highly loaded.
The object of the present invention is to provide a functional element which can be used with plastic components which enable relatively high strength connections to a further component irrespective of whether the further component is a plastic component or a component of metal, such as a sheet metal part or a solid part. Furthermore the functional elements should be able to be used in mass production and indeed without them suffering damage during transport as mass-produced goods which would make their ability to function questionable. Furthermore, in accordance with the invention, component assemblies should be provided using such a functional element and consisting of a functional element and a plastic component, which in operation enable high quality screw connections to further components. Moreover, a special die button and a method should be provided for the attachment of the functional element to a plastic component, whereby a system capable of functioning should be provided.